Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Homework Help: Location of roots problem.

  1. Aug 29, 2011 #1
    [SOLVED]
    1. The problem statement, all variables and given/known data

    Let[tex] 4x^2-4(α-2)xα-2=0 (α\epsilon R)[/tex]
    be a quadratic equation, then find the value of α for which both the roots are positive.

    2. Relevant equations



    3. The attempt at a solution

    the conditions will be
    1) Discriminant D≥0
    by this condition i got α (-∞,2][3,∞)
    2) f(0) greater than or equal to 0
    by this we get α (2,∞)

    3) now should i use -b/2a(point exactly between both roots)
    and equate as -b/2a greater than 0


    if-3rd point is right then what will be the final answer
    α (?,?)union(?,?)
    please provide help
     

    Attached Files:

    • iag94.png
      iag94.png
      File size:
      1,011 bytes
      Views:
      115
    Last edited: Aug 29, 2011
  2. jcsd
  3. Aug 29, 2011 #2

    PeterO

    User Avatar
    Homework Helper


    Are you sure the equation has typed up correctly? hopefully there should be a + or - sign between the x and the alpha??
     
  4. Aug 29, 2011 #3
    Thanks,
    I have solved the problem:smile:
    there is a + sign.
     
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook